odd ball questions for odd ball build

[nobled2]

I am a teacher working with students on a Solar Charged, electric motor, go kart. Pulled it out of mothballs last year, wired everything up and finished 2nd with borrowed batteries.

Some of the parameters on the charging side are going to change this year (not sure what yet) but we are trying to find ways to improve the kart overall, rolling resistance, less friction everywhere.

Better bearings and different front wheels/tires seem like a good start and we are open to suggestions

The kart we are working with is a Kandi Model 49FM5 with a Motenergy ME0909 electric motor powering it. We currently have 12 tooth sprocket on motor and 44 tooth on axle

 

[faultsafe]

? How many watts is that solar panel?

I feel like this is mostly being driven by the power of the battery and just trickle recharges via solar.

 

[ezcome-ezgo]

Premium bearings, super thin tires with loads of PSI in them. I'll leave the rest to your imagination.

 

[nobled2]

? How many watts is that solar panel?

I feel like this is mostly being driven by the power of the battery and just trickle recharges via solar.

It most definitely is driven by the batteries. The trick is to run the heat as fast as you can while not draining the battery down so far that it doesn't have time to recharge before next heat starts. Heats start every 30 minutes so if your heat takes 9 minutes to run 2 1.88 mile laps, you have 21 minutes to sit and charge.

We are running 3 270 watt panels now but that should change this year

Premium bearings, super thin tires with loads of PSI in them. I'll leave the rest to your imagination.

Good source and/or brand for bearings?? We are currently running small utility trailer tires on rear with 4x4 lug pattern with shorter wide tires mounted on 3 lug front hubs that I would love to swap out for hubs and bearings with same pattern (4x4 lug) as rear.

 

[ezcome-ezgo]

When I think about low rolling resistance, my mind congers up bicycle wheels. But they aren't necessarily suited to high side loading. So it will depend on what this vehicle will be expected to do in terms of performance.

 

[nobled2]

When I think about low rolling resistance, my mind congers up bicycle wheels. But they aren't necessarily suited to high side loading. So it will depend on what this vehicle will be expected to do in terms of performance.

It runs about 20-25 mph with low cornering forces (big long corners, track is almost a huge oval) but cart is relatively heavy (440lb without driver minimum). Not sure how bicycle wheels and tires would do but I do understand the idea....

Hoping to lose 100lb off the top of this thing next year by going to flexible panels instead of solid and moving more weight lower.

I have looked into bearings but thought someone here may be able to steer me in the direction of some competition type, low drag, bearings

We discovered last year that throwing a trailer hub on one end of the live axle that it was running made a world of difference in the way it ran

 

[Functional Artist]

Kool kart!
...but, Wow! ~600 lbs. with driver

What batteries are you using?

Go Power Sports & BMI karts both have lots of racing kart parts
...maybe contact either one of them for advice on bearings (they have spec sheets & everything)

 

[Denny]

Maybe check into ceramic bearings. Or a low viscosity grease like John Deere Corn head grease. It is a solid until the parts start to move then it turns into a liquid. Or you could try white lithium grease. Use as little as you can get away with without increasing friction. Experiment a little with different greases first and measure rolling resistance. Also higher air pressure in the tires will work wonders.

 

[nobled2]

Kool kart!
...but, Wow! ~600 lbs. with driver

What batteries are you using?

Go Power Sports & BMI karts both have lots of racing kart parts
...maybe contact either one of them for advice on bearings (they have spec sheets & everything)

Batteries are the limiting factor in the thing, can run up to 720 Watt-Hours (2 x 12 volt, 30 ah batteries). Makes the decision about how fast to go/ how much you can run down batteries and still be able to recharge for next heat a big deal.

Maybe check into ceramic bearings. Or a low viscosity grease like John Deere Corn head grease. It is a solid until the parts start to move then it turns into a liquid. Or you could try white lithium grease. Use as little as you can get away with without increasing friction. Experiment a little with different greases first and measure rolling resistance. Also higher air pressure in the tires will work wonders.

Last year we just ran some penetrating oil into the rear axle bearings to loosen them up (they hadn't turned in years) but obviously would prefer to upgrade. Better bearings combined with better grease couldn't hurt.

Would like to upgrade front tires but the only rims I see for that bolt pattern is the short wide rims. Would like to replace front hubs with something that will allow a 4x4" bolt pattern wheel so we can run small wheels and tires. Open to suggestions on that

 

[Denny]

Look at what Go power Sports has to offer I believe they have 4 on 4 front hubs then you can go to a taller skinny front tire. If not them try BMI or MFG Supply. I have seen them. Get new bearings and carefully peel out the seal and then wash out the boiled yack grease in them and refill with John Deere corn head grease. Should lower the rolling resistance some.

 

[nobled2]

Look at what Go power Sports has to offer I believe they have 4 on 4 front hubs then you can go to a taller skinny front tire. If not them try BMI or MFG Supply. I have seen them. Get new bearings and carefully peel out the seal and then wash out the boiled yack grease in them and refill with John Deere corn head grease. Should lower the rolling resistance some.

Decided to take the easy way out on front hubs, having one of the students (its an engineering class) design an adapter similar to what I would find on an automotive application. 1/2" steel or 1" aluminum plates to bolt onto hub with bolt pattern needed for rims and tires I want...

I do think pulling the seal out of existing hub to hit with a better grease is a great idea!!

 

[Denny]

I change the boiled yakk grease to higher quality grease all the time. Just have to be real careful picking out the seals to be able to reuse them.

 

[nobled2]

Didn't do as well this year as last year. Learning how the newer electronics (speed controller mainly) works was a big hill to climb for us.

Also trying to figure out how to read the Power Curve charts for the ME 0909 motor we're using. Too damn many lines on that chart for my old brain.

Does anyone know of a tutorial I can go to for help with that??

 

[nobled2]

Back at this again this year. Decided to make a change to 36v and needed to go to lithium to get range we need to make it work. Had problems getting kart to work with battery management stuff on lithium batteries before so trying something new. 3 motorcycle starter batteries paired with 3 deep cycle batteries the wired in series to get 36v.

https://www.amazon.com/EBL-Motorcyc...C1VN5HS/ref=psdc_404722011_t5_B091NYZMDP?th=1
https://www.amazon.com/gp/product/B0B7MBRC69/ref=ewc_pr_img_1?smid=A2NKEN9O69YXYL&th=1

had them hooked up in parallel then in series to get 36v, ran it on our track around the football field, and promptly dumped it over on its side. Too fast for a turn that sharp.

It now does 30 mph and those batteries work together to get it off the line and allowed it to recharge and start again.

 

[bob58o]

I’ve been watching a lot of Cletus McFarrlen and his attempts to go fast. I’m not sure how much of a factor wind resistance is at 25mph, but the face on the front doesn’t seem to be very aerodynamic. Maybe some light weight skins on the side of the kart would make it more slippery when cutting through the air.

wonder if wrapping the sides with plastic wrap would do anything?

 

[nobled2]

I’ve been watching a lot of Cletus McFarrlen and his attempts to go fast. I’m not sure how much of a factor wind resistance is at 25mph, but the face on the front doesn’t seem to be very aerodynamic. Maybe some light weight skins on the side of the kart would make it more slippery when cutting through the air.

wonder if wrapping the sides with plastic wrap would do anything?

I'd be scared to drive this thing if it got fast enough to worry about aerodynamics, lol That being said this was the result of our last test run:




Good news was there was no injuries, bad news is that this was at the other end of the track and I had to run down there to find nobody was hurt.... That and the obvious damage to one of the panels and the pvc rack we had them attached to

 

[Denny]

I dig the googlie eyes!

 

[nobled2]

I dig the googlie eyes!

The kids like it and it is kind of fun

 

[Master Hack]

I change the boiled yakk grease to higher quality grease all the time. Just have to be real careful picking out the seals to be able to reuse them.

If you take a small screwdriver and a belt sander, you can make a seal picker for yer bearings. Round it off sorta like a spoon. NO sharp edges.
Put it under the seal where it meets the inner race and lift carefully. I heard that this works, but can't say for sure.

 

[Denny]

May I ask, how they flipped it? Wind?